Various battery energized alarm systems are vulnerable to an unrecognized absence of battery power. Of course, in the absence of the battery power the alarm system is useless. At least one major city has an ordinance requiring the presence of smoke detectors in hallways of apartment buildings within particular classifications. In many instances these smoke detectors, although present as required by the ordinance, are inoperable because vandals have removed the batteries to use to power their radios, etc. Since the battery is mounted within the cover of the smoke detector its absence is not readily observable. Consequently, the tenants and operators of apartment buildings suffer from a false sense of security by the physical presence of the smoke detector under such circumstances.
Another situation that will occasion a similar false sense of security is where the battery has supplied power during the operation of the smoke detector to an extent such that it is depleted. For example, while a home owner is away from home a limited amount of smoke may occur, sufficient to set off the smoke detector, but the cause of the smoke not being sufficiently significant to alarm the home owner upon return. The smoke detector having been set off would continue to sound its horn until the battery is depleted. Since no one was present to hear the horn, upon the home owner's return there is no awareness that the battery has been depleted. This, of course, may occur with other types of battery operated alarm systems, as for example a sump pump alarm, etc.
The present invention is a visible alarm apparatus which will apprise an observer of the fact of occurrences such as those described above, which occurrences have resulted in the lack of battery power to the alarm device. One facet of the invention is the attaching of the cover of the alarm device to the battery by a clip so that in the absence of the battery, the cover will not remain in its normal location. Another facet of the invention is the use of a signal flag which is held in a concealed, or retracted, position by magnetic engagement with the diaphragm of the alarm horn. The sounding of the horn breaks that magnetic engagement and permits the signal flag to move to an exposed, or displaced, position thus signifying to an observer that the alarm has sounded even though the alarm is now silent as a result of the depletion of the battery power.